Is carbon storing a green solution?

West Virginia pioneers new technology to capture carbon and create 'green' power.

16 Nov 2009 13:30 GMT

For the state of West Virginia, whose vast coal deposits are an economic mainstay, carbon capture technologies offer hope of relieving the mounting political pressure to shift away from coal, now the fuel source for half of all US electricity output.

The technology of carbon capture and storage is a means to reduce the effects of global warming by 'capturing' carbon dioxide gas emitted from power plants and storing it beyond the reach of the atmosphere.

"We know that we must use coal in a more clean fashion," said Joe Manchin, West Virginia's governor, at the commissioning ceremony for the pilot project. "This is what we've demonstrated today - that it can be done."

The process involves cooling the carbon dioxide gas into a liquid state, then compressing and injecting it into shafts drilled more than 2km under the surface, below water tables and drinking water supplies. (For an animation of the process, click here).

The carbon dioxide (CO2) spreads through porous rock formations, similar to water filling up a sponge. It is prevented from rising up again by the same thick solid rock layers above that have kept oil and gas deposits trapped for millions of years.

Environmental groups are divided about carbon capture. Some dismiss the very possibility of clean coal, while others are worried that despite all assurances, some of the trapped CO2 could eventually escape.

Then there is the added cost.

By most estimates, the retail price of electricity from low-carbon coal could be more expensive than nuclear or solar power.

To make carbon burial commercially practical, billions of dollars in government subsidies would be required.

Low-carbon burning plants

For the long-term, some experts are calling on the US and China, the world's number one CO2 polluter, to collaborate on a crash programme of building new low-carbon- burning coal plants.

In a new report, the Asia Society of the US, an institution which works to improve Asia-US ties, says: "Both countries will continue to depend on burning large amounts of coal for the foreseeable future, and thus, if this technology can be proven at sufficient levels of scale and safety, the deployment of CCS [carbon capture and storage] technologies is an essential element in any effort to stabilise global greenhouse gas emissions."

But even if carbon capture clears all its technical and economic hurdles, sceptics say it might take another 15 to 20 years to start making a noticeable difference in the world's CO2 output.

Without an ambitious investment in the technology, however, the fight against global warming could well be futile.